Is it normal to feel sad after masturbation?

I discovered self-pleasure when I was only seven years old. I am 20 now and I lost my virginity to a guy I barely knew because I wanted someone to love me. I promised myself I would never make that mistake again, but it seems that all the guys I go out with just want me for their own personal pleasure. I honestly feel less guilty by myself then with a partner. But I still want a boyfriend and someone who really loves me and respects me to have sex with. I just feel incredibly lonely after using my vibrator because I feel like I will never find the right guy, and I don't just want casual sex with anybody, I want someone who loves me. A girl once told me in high school that "You better go out and buy a vibrator because that is the only love you will ever get" and I think that is the root of my problem because that has always stuck with me. I just feel sad after masturbating because I feel like I will never have more, or if I did have sex it would be because the guy is using me.